The Method: For Khadijah Queen, Wellman prescribes two shades of a permanent foam dye—dark brown for her gray roots and rich cherry for the length of her hair. "Foam dyes are the best choice for women who have very thick hair," he says. Why two colors? Applying brown from roots to ends could create a severe, monotone effect, and putting cherry or mahogany shades on gray hair can result in a pink tint. Together, though, the colors cover gray and create a vibrant shade with subtle dimension.